As wireless communication systems for a cellular phone or the like, there presently are a plurality of systems corresponding to each standard. Cellular phone systems widely used in Japan are, for example, PDC (Personal Digital Cellular), CDMA (Code Division Multiple Access), PHS (Personal Handyphone System) and the like. In addition, WiMAX (Worldwide Interoperability for Microwave Access) is becoming popular as one of new systems being suggested in recent years for a wireless broad band that takes a crucial part in ubiquitous age.
Although the wireless communication apparatus normally corresponds to one of standards, it is becoming popular to have a multiband or a multimode wireless communication apparatus because of popularization of the cellular phones accompanied by tightening of the frequency range allocated to each system and, for example, a dual band communication apparatus capable of accepting two different communication systems of PDC and W-CDMA (Wideband Code Division Multiple Access) is known (see Patent Documents 1 and 2, for example). Recently, there is being developed a wireless communication apparatus capable of hybrid performance such as hand-off between different frequency ranges or seamless hand-off between different systems in order to provide a stable and highly functional service.
Shown in FIG. 10 is a block diagram illustrating an example of a conventional wireless communication apparatus used for the CDMA system. The wireless communication apparatus 100-1 has CDMA system of 800 MHz band (for example, ARIB STD-T53: Association of Radio Industries and Businesses STANDARD-T53) and CDMA system of 2 GHz band (for example, ARIB STD-T64). Furthermore, the diversity scheme is adopted for data communication (for example, cdma2000 1×EV-DO: 1× Evolution Data Optimized) of both the CDMA system of 800 MHz band and the CDMA system of 2 GHz band for the purpose of either improvement in throughput or hybrid performance.
As shown in FIG. 10, the CDMA system of 800 MHz band is provided with a transmitting circuit 101, a receiving circuit 102, a duplexer (DUP) 103 for separating transmitted and received signals of 800 MHz band, and a secondary receiving circuit 121, while the CDMA system of 2 GHz band is provided with a transmitting circuit 111, a receiving circuit 112, a duplexer (DUP) 113 for separating transmitted and received signals of 2 GHz band, and a secondary receiving circuit 131.
As common units for both of the CDMA systems, the wireless communication apparatus 100-1 has a primary antenna (ANT) 151, a first external connector 152 comprising a measuring RF (Radio Frequency) connector for instance, a diplexer (Dip) 153 for sharing the primary antenna 151 with 800 MHz band and 2GHz band, a secondary antenna (ANT) 161, a first external connector 162 comprising a measuring RF connector, and a diplexer (Dip) 163 for sharing the secondary antenna 161 by the secondary receiving circuit 121 of 800 MHz band and the secondary receiving circuit 131 of 2 GHz band.
The transmitting circuit 101, the receiving circuit 102 and the secondary receiving circuit 121 of the CDMA system of 800 MHz band are connected to a baseband unit 500. Likewise, the transmitting circuit 111, the receiving circuit 112 and the secondary receiving circuit 131 of the CDMA system of 2 GHz band are connected to the baseband unit 500.
For 1×EV-DO communication with the CDMA system of 800 MHz band, for instance, by the wireless communication apparatus 100-1 shown in FIG. 10, the transmitted signal from the transmitting circuit 101 is radiated from the primary antenna 151 by way of the duplexer 103 and the diplexer 153, while the received signal of 800 MHz band received by the primary antenna 151 is received by the receiving circuit 102 by way of the diplexer 153 and the duplexer 103. Furthermore, the received signal of 800 MHz band received by the secondary antenna 161 is diversity received by the receiving circuit 121 by way of the diplexer 163.
Similarly, for 1×EV-DO communication with the CDMA system of 2 GHz band by the wireless communication apparatus 100-1, the transmitted signal from the transmitting circuit 111 is radiated from the primary antenna 151 by way of the duplexer 113 and the diplexer 153, while the received signal of 2 GHz band received by the primary antenna 151 is received by the receiving circuit 112 by way of the diplexer 153 and the duplexer 113. Furthermore, the received signal of 2 GHz band received by the secondary antenna 161 is diversity received by the receiving circuit 131 by way of the diplexer 163.
The wireless communication apparatus 100-1 monitors a voice incoming call by regularly receiving notification information (paging) notifying the call from a base station in 1× communication. Therefore, during 1×EV-DO communication with either the CDMA system of 800 MHz band or the CDMA system of 2 GHz band, the wireless communication apparatus 100-1 regularly switches the system to 1× communication at the side of the primary antenna 151 to receive paging, or maintains 1×EV-DO communication at the side of primary antenna 151 to improve throughput and regularly switches the system to 1× communication at the side of the secondary antenna 161 to receive paging.
Shown in FIG. 11 is a block diagram illustrating another example of a conventional wireless communication apparatus used for the CDMA system. The wireless communication apparatus 100-2 is provided with an antenna switch 172 having four contact points a to d instead of the diplexer 153 in FIG. 10. The antenna switch 172 is controlled based on a control signal from the baseband unit 500 so that only the duplexer 103 is connected to the primary antenna 151 by way of the contact point a or to a secondary external connector (Ext) 171 serving as an external antenna connecting interface to which an external antenna can be connected, by way of the contact point b, or so that only the duplexer 113 is connected to the primary antenna 151 by way of the contact point c, or to the secondary external connector 171 by way of the contact point d. The primary antenna 151 and the secondary external connector 171 are thus shared by both the CDMA systems of 800 MHz band and of 2 GHz band. Since other constitutions and performances are the same as those of the wireless communication apparatus 100-1 in FIG. 10, the corresponding units are provided with the same reference symbols and the descriptions thereof will be omitted.
Shown in FIG. 12 is a block diagram illustrating an example of a conventional wireless communication apparatus used for the WiMAX system. The wireless communication apparatus 200 is for the WiMAX communication of 2.5 GHz band and provided with a transmitting circuit 201, a receiving circuit 202, a switch 253 with two contact points a and b, and an antenna (ANT) 251. The transmitting circuit 201 and the receiving circuit 202 are connected to the baseband unit 500.
A complex communication system adopted by the WiMAX system is not Frequency Division Duplex (FDD) adopted for the CDMA system shown in FIG. 10 and FIG. 11 but Time Division Duplex (TDD). The wireless communication apparatus 200 thus controls the switch 253 based on the control signal from the baseband unit 500 in synchronization with transmitting and receiving so that the transmitted signal from the transmitting circuit 201 is radiated from the antenna 251 by way of the contact point a of the switch 253 in a transmitting frame (uplink) and the received signal received by the antenna 251 is received by the receiving circuit 202 by way of the contact point b of the switch 253 in a receiving frame (downlink).
The wireless communication apparatus 200 shown in FIG. 12 is further provided with an antenna (ANT) 261 and a secondary receiving circuit 211 to perform diversity receiving. The secondary receiving circuit 211 is connected to the baseband unit 500. A first external connector 252 comprising a measuring RF connector is provided between the antenna 251 and the switch 253, while a first external connector 262 comprising a measuring RF connector is also provided between the antenna 261 and the secondary receiving circuit 211.
A multimode wireless communication apparatus usable for both the CDMA system and the WiMAX system is conceivable as another wireless communication apparatus. When seamless hand-off between systems or the like is performed in such multimode wireless communication apparatus, it is necessary to run both systems simultaneously. It is preferable for each of the systems to share the same antenna in light of downsizing and the cost.
A multimode wireless communication apparatus 300 shown in FIG. 13 is suggested as an example of such multimode wireless communication apparatus. The multimode wireless communication apparatus 300 is a combination of the wireless communication apparatus 100-1 of the CDMA system shown in FIG. 10 and the wireless communication apparatus 200 of the WiMAX system of 2.5 GHz band shown in FIG. 12. As shown in FIG. 13, each antenna terminal of the duplexer 103 of the CDMA system of 800 MHz band, of the duplexer 113 of the CDMA system of 2 GHz band and of the switch 253 of the WiMAX system of 2.5 GHz band is connected, by way of a triplexer (Tri) 353, to an antenna (ANT) 351 that accepts three bands of 800 MHz band, 2 GHz band and 2.5 GHz. A first external connector 352 comprising a measuring RF connector is provided between the triplexer 353 and the antenna 351.
An antenna (ANT) 361 that accepts three bands is connected, by way of a triplexer (Tri) 363, to secondary receiving circuits 121, 131 and 211 corresponding to each band. A first external connector 362 comprising a measuring RF connector is provided between the antenna 361 and the triplexer 363.
The transmitting circuit 101, the receiving circuit 102 and the secondary receiving circuit 121 of the CDMA system of 800 MHz band are connected to the baseband unit 500, and so are the transmitting circuit 111, the receiving circuit 112 and the secondary receiving circuit 131 of the CDMA system of 2 GHz band and the transmitting circuit 201, the receiving circuit 202 and the secondary receiving circuit 211 of the WiMAX system of 2.5 GHz band.
A multimode wireless communication apparatus 300 shown in FIG. 13 is provided with the triplexer 353 to share the antenna 351 among the CDMA system of 800 MHz band, the CDMA system of 2 GHz band and the WiMAX system of 2.5 GHz band and also provided with the triplexer 363 to share the antenna 361 among the secondary receiving circuits 121, 131 and 211 of each system.
FIG. 14 shows another example of the multimode wireless apparatus. The multimode wireless communication apparatus 400 is a combination of the wireless communication apparatus 100-2 of the CDMA system shown in FIG. 11 and the wireless communication apparatus 200 of the WiMAX system of 2.5 GHz band shown in FIG. 12. That is, in addition to the constitution shown in FIG. 13, in the multimode wireless communication apparatus 400, the antenna terminal of the triplexer 353 is provided with an antenna switch 451 having two contact points a and b. The antenna switch 451 is controlled based on the control signal from the baseband unit 500 to selectively turn on the switch at the contact point a or b, thereby the antenna 351 and the second external connector 171 are shared among the CDMA system of 800 MHz band, the CDMA system of 2 GHz band and the WiMAX system of 2.5 GHz band. Other constitution is the same as that of the multimode wireless apparatus 300 in FIG. 13.    Patent Document 1: Japanese Patent Laid-Open No. 2003-188759    Patent Document 2: Japanese Patent Laid-Open No. 2004-023536